Lubricant



Patented Jan. 23, 1945 2,868,023 LUBRICANT tion of Maine No Drawing. Application April 24,1943, Serial No. 484,469

3 Claims.

This invention relates to an improved turbine oil. It relates more particularly to a lubricating oil composition consisting principally of a petroleum lubricating oil, the characteristics of the oil being modified by the addition thereto of a relatively small proportion of bis-(piperidinemethyl) -para-tertiary-amylphenol.

A lubricating oil composition to be used as a turbine oil, and especially in modern marine steam turbines, is subject to very exacting re quirements. Not only must it perform the ordinary function of lubricating the turbine over prolonged periods without interruption but usually it must serve as a coolant, to lubricate the gear- I ing mechanism and to operate oil-actuated governors or control mechanisms having very nice turbine oil. This is probably due primarily to the fact that in normal use turbine oils rapidly become contaminated with water. Whatever the cause, it is generally recognized that the performance of a turbine oil is not predictable from conventional tests applicable to other oil lubricants' Essential characteristics of a satisfactory turbine oil include, in addition to ordinary lubricating requirements, extraordinary resistance to oxidation and emulsion in the presence of water. It is also of importance to avoid rusting of the metal parts within the oil system of the turbine and auxiliary apparatus under operating conditions.

Theuse of many lubricating oil compositions, otherwise satisfactory as turbine oils, has resulted in the oxidation of the oil and the rusting of metal parts within the oil system with consequent serious interference with the operation of the turbine including the oil-actuated governors and other parts, depending upon close tolerances. The results of such rusting not onl interfere with the operation of and tend to clog the delicate clearances of the oil system but the products of the rusting. appear to catalyze oxidation of the oil with resultant sludge formation which may further aggravate such conditions. The products of such rusting also appear to act as emulsifying agents.

We have found that the previously experienced oxidation of the turbine oil may be substantially inhibited by incorporating in the oil a minor amount of bis-(piperidinomethyl) -p-tert.-amylphenol.

The herein-referred-to bis- (piperidinomethyl) p-tert.-amylphenol used in the compounding of equipped with a thermometer, dropping funnel, and a motor-driven stirrer, 82 grams (0.5 mol.) of para-tertiary-amylphenol, 106 grams of 93% pure piperidine (1.16 mols.) and 150 c. c. of methyl alcohol. While maintaining the temperature of the resulting solution within the range of 68-'77 F., there was added thereto, with stirring,

over a period of '70 minutes, 33 grams (1.1 mols.)

of formaldehyde as a 34% formalin solution. The reaction mixture was then stirred for 2 hours at a temperature of 80 F. and thereafter heated on a steam bath for 2 hours using a reflux condenser to return volatile material to the flask. Any moisture and unreacted materials present were then distilled ed by heating on an oil bath at an absolute pressure of 0.7 mm. of mercury, the oil bath temperature being 300 F. By this procedure a yield of 166 grams of the crude bis-(piperidinomethyl) -p-tert.-amylphenol was obtained as a viscous orange-colored liquid residue with a greenish cast. This yield was equivalent to 92.8% of the theoretical yield.

In referring to bis-(piperidinomethyl) -p-tert.'- amylphenol herein and in the appended claims we refer to the above-described product although,

of course, we intend to refer by this term to the Y same material by whatever process it may be made. It is understood that our invention is not predicated upon the identification of the addend as a matter of terminology,

The lubricating oil constituent of our improved turbine oil may consist of a petroleum lubricating fraction, such as ordinarily specified for turbine oils. It may with advantage be a highl refined lubricating oil, for instance an acid-treated petroleum lubricating oil fraction or one which has been subjected to solvent refining, such as a phenol-treated fraction from East Texas crude. The solvent-refined oils have generally been found more resistant to sludging. For example, phenol-treated East Texas neutrals having the following characteristics have been used with advantage:

Sample I Sample II Gravity, A. P. I 28.9 26. 5

ash F 405 400 Fire F" 455 455 Viscosity at F., S. S. 192. 3 228. l Viscosity at 210 F., S. S. U 45. 3 46. 9 Viscosity index (Dean & Davis) 87.1 79. 2 Pen F +10 +5 Neutralization N0 0.025 0.05 Saponification No 0.27 0.27 Carbon residue (Com 0. 031 0. 044 Ash O. 000 0.002 Sulfur "do..." 0. 21 0. 34 Steam emulsion No 1 42 Demulsibility 1, 620+ 600 The steam emulsion numbers appearing in the foregoing tabulation were determined in accordance with the method designated Standard y r 2,368,023 j UNITED STATES PATENT OFFICE method of testing for steam emulsion of lubricating oils, A. S. T. M., D157-36.

The demulsibility values appearing in the foregoing tabulation weredetermined in accordance with the method designated Demulsibility test for lubricating oils prescribed by Federal Standard Stock Catalog, section IV, (part 5), Federal Specifications for Lubricants and Liquid Fuels, General Specifications (Methods for Sampling and Testing), VV-L-791a, Qctober 2, 1934, Method 320.32.

The unique requirements of a turbine oil have resulted in' the formulation of a special test method for determination of the characteristics of the oil with respect to oxidation. The results of oxidation tests herein noted were obtained in accordance with the method prescribed by the American Society of Testing Materials and designated Proposed method for determining oxidation characteristics of turbine oils, section III, Technical Committee C, A. S. T. M., Committee D2, July 2,1941.

By incorporating a minor proportion of the bis- (piperidinomethyl) -p-tert.-amylphenol in a suitable lubricating oil constituent, oxidation of the oil under conditions to which turbine oils are subjected is materially inhibited. Depending upon the severity of the oxidation conditions involved, including temperature, access of air to the oil, amount of water present and the amount of salt or the like in the oil, the proportion of the addend used may with advantage be varied from about 0.05% to about 1% by weight of the oil.

For example, the oxidation induction period of the East Texas phenol-treated neutral previously identified herein as Sample II, was found by the previously identified test for determining the oxidation characteristics of turbine oils to be 150 hours. By compounding with this oil 0.2% of the bis(piperidinomethy1) -p-tert.-amylphenol, the oxidation induction period of the resultant turbine oil was increased to 300 hours. By the incorporation of 0.5% of this addend in the oil, the oxidation induction period was increased to 450 hours and, by the addition of 0.8% of the addend, the oxidation induction period was increased to 790 hours.

The ability of the addend of the present invention effectively to inhibit oxidation of turbine oils is unexpected and not readily accounted for. This s is particularly evident from the fact that other similar compounds have been found to be either inert or p-ro-oxidantunder conditions encountered by turbine oils. Examples of uch compounds ineffective as anti-oxidants in turbine oils are bis- (diamylaminomethyl)-p-tert.-amylphenol, morpholinomethyl-p-tert.-amylphenol and morpholinomethyl phenol.

In the compounding of our improved turbine oil, a small amount of the above-identified addend is admixed .with a suitable petroleum lubricating oil in the conventional manner of compounding such oil compositions. In addition to the lubricating oil constituent and the addend previously described, various other addition agents having the ability favorably to influence the characteristics of the turbine oil may be incorporated in the improved turbine oil of our present invention further to improve the properties thereof in various respects.

A further essential characteristic of turbine oils is that they do not form objectionable emulsions under conditions of use. Consequently, in the compounding of such oils, it is necessary to avoid the use of addends which might deleteriously affect the emulsibility of the oil. A further advantage of our improved turbine oil i that the satisfactory emulsifying characteristics of the base oil are not destroyed by the addition of the his- (piperidinomethyl) -p-tert.-amylphenol.

A further notable characteristic of our improved turbine oil is its ability to Withstand contamination by water without material separation of the addend from the oil or substantial deterioration of the addend itself.

As previously indicated, depending upon conditlons of use, the addend may with advantage be used in proportions ranging from about 0.05% to 1% on the weight of the oil. Proportions even in excess of 1% tions have not been found necessary. Though proportions less than 0.05% may be used, much. smaller proportions are usually not sufficiently effective. Accordingly, about 0.05% mended.

We claim:

1. .An improved turbine oil which comprises a petroleum lubricating oil containing an amount of bis- (piperidinomethyl) -para-tertiary-amylphenol eifective to retard oxidation of the oil.

2. An improved turbine oil which comprises a petroleum lubricating oil containing about 0.05% to about 1% of bis-(piperidinomethyl) -para tertiary-amylphenol.

proportions ranging from to about 1% are generally recom- 3. An improved turbine oil which comprises apetroleum lubricating oil containing about 0.2%

to about 1% of bis-(piperidinomethyl) -para-tertiary-amylphenol.

ROBERT D. HERLOCKER. MILTON PAUL KLEINHOLZ. FRANKLIN M. WATKINS.

may be used but such larger propor- 

